1. Field of the Invention
The present invention concerns a fan of a turbine engine, such as an aircraft jet engine or turboprop engine.
2. Description of the Related Art
In a known fashion, a turbine engine fan comprises a rotor disc having at its external periphery a plurality of longitudinal ribs delimiting between them slots for the axial mounting and radial retention of blade roots. The downstream end of each rib comprises a radial lug comprising an orifice for a screw or bolt to pass for fixing the fan disc onto an upstream flange of a low-pressure compressor arranged downstream of the fan. The low-pressure compressor is thus driven in rotation with the rotor of the fan by a turbine shaft.
The flanks of each lug form stops for retaining the blades and thus limit their angular movement. In the event of loss of a blade, the blade disconnected from the disc impacts an adjacent blade, which tilts angularly and comes into abutment on the flank of a lug, which transfers the energy released by the impact of the disconnected blade on the adjacent blade to the whole of the disc and thus prevents losses of blades in a cascade.
When the aircraft is on the ground and the turbine engine is stopped, the rotating parts of the turbine engine may undergo autorotation (referred to as “windmilling”). This is because the air entering the turbine engine causes a rotation of the rotor of the fan at a speed of around 40 to 50 revolutions per minute. This low rotation speed does not allow sufficiently great centrifugation of the blades for locking thereof in position in the slots. As a result the blades of the fan may tilt on the flanks of the lugs of the disc ribs. These repeated contacts cause rubbing between the flanks of the lugs and the blades, leading to premature wear on the stops, which requires more frequent repairs to the stops.
At the present time, repair to the flanks of the lugs is carried out by plasma deposition of a metal layer. However, the lugs of the disc thus repaired have a lower fatigue strength than that of the lugs of a new disc. In addition, these depositions of material have limited impact resistance and may progressively disintegrate over time.
Finally, this operation cannot be performed under the wing and requires dismantling and repair in a maintenance workshop, which leads to lengthy and expensive immobilisation times and requires the use of expensive and complex tooling.